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Poster: Javik Date: Nov 28, 2006 3:54pm
Forum: petabox Subject: Understanding all that technical blather :-)

Learning about SAS and expander technology is quite a challenge, so this is my simple breakdown of what I think the facts about this chassis, for the rest of us SAS/SATA dummies.

1. The 933E1/933E2 chassis CAN have a motherboard installed, but is not required to have a motherboard installed. You can use it without a motherboard by instead using a tiny power control board from SuperMicro:

CSE-PTJBOD-CB1 - JBOD Storage Power-up Control Board

This part is listed at the bottom of the chassis product page, in the optional parts list:

*** Told to me directly by SuperMicro support

2. A 933E1/933E2 chassis with just the power board can be cascaded (daisy-chained) onto another 933E1/933E2 chassis using external SAS cabling to interconnect them, and presumably internal cabling to bring out the SAS ports on the back of the chassis.

NOTE: So far I do not know what SuperMicro cabling or internal-to-external port-brackets are needed to do that. I am still looking for more information.

3. SuperMicro's port expander system seems to be using 3 incoming and 3 pass-through cable connectors. If you just use 1 port and 1 SAS controller, you can cascade about 10 chassis for 128 drives on one channel. Use two SAS controllers, and you cascade 20 chassis for 256 drives on two channels, and three SAS controllers and 30 chassis for 384 drives on three channels.

(NOTE: The interconnect method is not spelled out in this manual, and I am making a guess at how it works. I need to research this some more, and ask more questions of their tech-support.)

4. Although the 933E1/933E2 chassis requires an SAS controller and uses SAS technology it is fully compatible with cheap SATA hard drives.

So if you do not need the expensive, fast, and ultra-reliable SAS, and just are going for huge bulk storage with cheap 500gig SATA drive, you can do that.

NOTE: It appears to me that the expanders handle the cascading, so using SATA has no effect on the number of drives supported. The expanders should support 128/256/384 drives, whether SAS or SATA.

5. The 933E1 chassis and 933E2 chassis are essentially identical, and can be used in a similar cascaded fashion. However, the 933E2 also provides a redundant backplane channel for SAS drives that offer redundant signal paths.

- If you intend to use cheap SATA hard drives to build your huge array, you only need the 933E1 since cheap SATA drives will not be able to use the redundant datapath.

- Make sure the SAS drives you are purchasing have dual-path capability or you'll get no benefit from the 933E2 chassis.

I still haven't seen any pricing information for either the 933E1 or the 933E2 chassis. I will keep looking. If you find out any more about this please post it.


This post was modified by Javik on 2006-11-28 23:54:45

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Poster: elhoim Date: Jan 11, 2007 6:39am
Forum: petabox Subject: Re: Understanding all that technical blather :-)

Maybe this article can help?

I am in a hurry and thus not (yet) enough time to read completely....